Minimum predicted distance: Applying a common metric to collision avoidance strategies between children and adult walkers

Collision avoidance strategies between two athlete walkers: Understanding impaired avoidance behaviours in athletes with a previous concussion

“…Minimum Predicted Distance (mpd), was analyzed as a function of time throughout the interaction period to examine contribution to collision avoidance between athletes. Comparing initial response to collision avoidance, the threshold for motion adaptation between two control athletes (ATH-ATH) was similar to previous findings in young adults (~1m) [17][18][19][20]. However, when two CONC interacted (CONC-CONC), risker collision avoidance strategies manifested in a smaller adaptation threshold (0.84m).…”

“…Likewise, the contribution to collision avoidance differed between ATH and CONC groups based on crossing order and who was interacting. Similar to previous studies with young adults, two control athletes interacting were able to establish role-dependent strategies such that, the individual passing second contributed more to the collision avoidance(Figure 3a) [17][18][19][20].…”

“…It is important to note that ATH and CONC did have an overall smaller clearance distance compared to previous literature with young adults. Smaller clearance distances may be J o u r n a l P r e -p r o o f due to athletic training, however adaptions to mpd(t) were consistent between control athletes and previous collision avoidance literature [17][18][19][20]. Additionally, all interactions compared avoidance behaviours of athletes of the same sex and similar size, therefore collision avoidance behaviours are not based on physical characteristics [21], rather based on perceptions of the other pedestrian's movements.…”

“…The mutual avoidance between two pedestrians during a 90°-collision avoidance task can be described using the evolution of Minimum Predicted Distance (mpd), which predicts the future risk of collisions between two walkers [17][18]. In such as task, role-dependent strategies can be identified based on crossing order such that, the walker passing second contributes more to the avoidance situation compared to the walker passing first, regardless of age [18][19]. These roledependent strategies are established at the initial sight of one another and are maintained throughout the entirety of the avoidance task such that, the walker who is intended to pass first at the beginning of the interaction (based on walkers' respective velocity and position) is the one who passes first at the time of crossing [18,21].…”

“…These roledependent strategies are established at the initial sight of one another and are maintained throughout the entirety of the avoidance task such that, the walker who is intended to pass first at the beginning of the interaction (based on walkers' respective velocity and position) is the one who passes first at the time of crossing [18,21]. This 90-collision avoidance task and mpd analyses has proved to be an effective paradigm to quantify avoidance behaviours (i.e., contribution to avoidance, role identification to the avoidance, and temporal evolution of an avoidance) across the lifespan, highlighting visuomotor changes due to development and aging [19][20].…”